Troubleshooting NC Error Code on a Tekonsha Prodigy P2 # 90885 Electric Trailer Brake Controller

Question:

I connected the unit the way the directions advised. When i press the brakes the number reading pops up then the NC does. I check the trailer and found no problems. I also just bought this trailer so i ciontacted the previous owner and he stated he had no issues with his break controller reading the trailer. any thoughts?

Expert Reply:

There are 4 potential problems that are stated in the instructions (linked below) that could cause the NC (no connection) reading on your Prodigy P2, item # 90885. I have also included a couple of links to wiring and brake controller information. The 4 possible causes for NC are as follows.

1. Trailer not connected to tow vehicle.
2. Trailer connected with open circuit on brake line.
3. Trailer connector disconnected or corroded.
4. Loss of trailer brake magnet ground.

The most likely in your case is that the 7-way connector on the vehicle has some corrosion in it that is causing a slight short between the brake output connection and the ground connection. This corrosion may be evident inside the connector by opening the cover or it may be inside the connector at the wire connections.

If this is not the issue, I would then go to the brake controller itself. Sever the blue brake output wire and then apply the manual slide. Using a circuit tester, item # 3808 if needed, you should get output to the trailer brakes. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly also then the problem is farther back either in the vehicle wiring or on the trailer.

If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire and on the red wire ONLY when the brake pedal is pressed.

If there is power on the red wire before the brake pedal is pressed you have connected the red wire from the brake controller to the wrong circuit. You would then need to find the brake switch wire that has power ONLY when the brake pedal is activated.

If these connections check out and the brake controller is properly grounded to the negative battery terminal then there is possibly a problem inside the brake controller.

If everything shows good on the vehicle, you will need to check the trailer for bad magnets and/or ground connections.

expert reply by:
Robert G

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